Pressure regulator



Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE Application May 29,

3 Claims.

The object of thisl invention is to improve the operationl of theelectric switch, which is used in connection with the diaphragm of avacuum or pressure regulator. Inv such an apparatus, the

actuating fluid operates on the surface of a spring or weight presseddiaphragm which is connected to the switch, and the parts are arrangedso that when certain pressures or vacuums are reached, the switch willbe thrown to cut the operating means, usually an electrically drivenpump, out of and into operation.

An electrical switch'must open with a snap action to prevent arcing andfor this purpose the switch is usually provided with a mechanicallyacting snap or tip over mechanism. In

using such a vacuum pressure regulator, I havel half inch below anaverage of twenty-one and one-half inches, or within a range of one inchof mercury. With the old arrangement, the finest range of adjustmentpossible was three inches of mercury and, therefore, it was necessary tohave the pump start in operation at twenty-one inches and to cut out, topull a vacuum up to twenty-four inches, which with hot returns oftencaused the pump to run all the time.

I discovered that this diiiiculty can be overcome by removing-themechanical snap action switch from an ordinary vacuum pressure regulatorand-by substituting therefor a single tilting mercury switch operatedfrom the diaphragm and adjusted so that the drag of the mercury againstthe electrode or electrodes, as well as the friction of the mercury inits containing ture, will cause a delayed action, which will effect asmall but actual diierence in pressure between the on and oi positionsof the switch and which will cause the switch to open with a snapaction. With this arrangement I can easily control the on and onpositions of the switch within the range of an inch of mercury.

One embodiment of the invention is illustrated in the accompanying sheetof drawings, in which:-

Fig. l is a sectional plan view of the improved apparatus.

Fig. 2 is a central sectional elevation, and

1935, Serial No. 24,139

Figs. 3 and 4 are partial sectional elevation to illustrate the peculiaraction.

Referring to the drawing and in detail,' I0 designates a bottom plate,and II a cover plate, a diaphragm I2 being secured between IU and 5 II,andv these parts being held together by screws I3.

The actuating fluid is permitted to operate on the upper side of thediaphragm I2 through a coupling III) on the upper or cover plate Ii, 10to which coupling a pipe can be connected.

Where the switch is to be used asa pressure regulator, the actuatingiluid is admitted to act on the lower side of the diaphragm through acoupling IDG, illustrated in dotted lines in Fig. 16 2, attached to theplate I0, the largevent opening in which is then closed.

Upper and lower plates I5 and I4 are placed on the sides of thediaphragm I2 and held thereto by a screw I6 threadedinto a nut I1. Asupplemental diaphragm I8 is placed on top of the cover plate vII andheld in position thereon by a packing ring I9, a plate 22, and screws2i, threaded into the plate 22.

A supplemental contact 23 having a pin 24 bears on the supplementaldiaphragm I8 and through the same on the large nut I1.

An inverted U--shaped bracket 25 is held on the base 22 by screws 26. Anoperating spring 21 is housed in the bracket 25, the lower end of thespring being contained in a thrust block or cup 28 in which the pin 24is fitted. A screw 29 extends down inside of the spring 21, the screwhead being fitted in the top of the bracket 25 and having an integralcollar 30 bearing against said bracket. The spring 2'I bears on a nut 32threaded on the screw 29 so that by turning the screw the pressure ofthe spring can be adjusted.

A tilting plate 33 is pivoted by screws 34 to the sides of the bracket25. The thrust block 28 is provided with arms 35 which are connected lbyscrews 36 to tilting plate 33. One side of the tilting plate 33 isextended, as at 31, and is provided with' a screw 38 having a check nut39, the screw being set in position to engage the head of a pin 40sli-ding in a bracket 3I on plate 22, a spring 4I being arranged on thepin 40.

lWhen the screw 38 is backed "away so that it can never come in contactwith the plate 40 throughout the travel of the extension arm 31, theswitch will open and close with aminimum diierence in pressure.

By adjusting the screw 38 so that it comes in contact with the plate 40through a portion of the travel of the extension arm 31, the switch maybe adjusted to open and close with a greater diiferential in pressure.

The tilting plate 33 is provided with an arm 42 carrying a clamp 43 heldthereto by screw 44.

A mercury switch 45 is secured in said clamp 43. This mercury switchconsists of a tube from which the air is exhausted and a globule of mer`cury M. One`or more electrodes 48 and 41 is or are sealed into the tubeof the mercury switch 45 and suitable lead in wires 48 and 49 areconnected thereto.

The parts` as thus far described can be adjusted to get a very delicateoperation with the switch.

Assuming that the device is used as a vacuum pressure regulator, underthe gures previously described, when the switch is closed the same willbe in the position shown in Fig. 2. As the vacuum on top of thediaphragm I2 is increased, the atmospheric air pressure on the underside of said diaphragm will tilt the left hand end of the mercury switch45 to its critical position,v as shown in Fig. 3. In this position theglobule of mercury M will tend to run or flow to the right, but will beheld from so doing by the relud ance of the mercury to move past theelectrode or electrodes.

As the vacuum now slightly increases, the tendency of the mercury toflow by gravityto the right will overcome this resistance to iiow, andthe mercury switch will move to its open position, as shown in Fig. 4.

Thus there will be a snap action of the parts between the position shownin Figs. 3 and 4. which is measured by the said retarding effect of themercury. This factor of resistance to dow can be made much less than theextra pressure necessary to obtain the throw of the switch to overcomeany mechanical snap mechanism. Therefore, the mechanism describedprovides a snap switch which can be very delicately adjusted.

I am aware that itis common to tilt a mercury switch by a fluid actingon a diaphragm, corrugated bellows or piston, but so i'ar as I am aware,the resistance to flow of a globule of mercury has never been employedas the sole means of providing for the necessary snap action.

,The details and arrangements herein described may be greatly varied bya skilled mechanic without departing from the scope of my invention asexpressed in the appended claims.

Having thus fully described my invention, what I claim and desire tosecure by Letters Patent is:-

,1. A pressure regulator comprising a diaphragm on the surface of whichan actuating fluid operates, adjusting means for determining thepressure at which said diaphragm operates, and a tilting mercury switchmounted for movement under the influence of said diaphragm, means tocushion movement'of said switch, said mercury switch having an electrodepositioned at a substantial angle to and in the path of flow of themercury and positioned to offer an obstruction to such flow of mercurywhereby adhes'on of the mercury to the electrode will in itself cause adelayed action of the switch followed by an actuation of the switch witha snap action.

2. A pressure regulator comprising a diaphragm on the surface of whichan actuating uid operates, adjusting means for determining the pressureat which said diaphragm operates, a tilting plate connected to saiddiaphragm for direct actuation thereby, adjustable means to cushiondownward movement of said tilting plate, and a tilting mercury switchmounted on said plate for movement therewith, said mercury switch havingan electrode positioned at a substantial angle to and in the path offlow of the mercury and positioned to oier an obstruction to such flowof mercury whereby adherence of the mercury to the electrode will initself cause a delayed action of the switch followed by an actuation ofIthe switch with a snap action.

3. A pressure regulator comprising a diaphragm on the surface of whichan actuating uid operates, adjusting means for determining the pressureat which said diaphragm operates, a tilting plate fulcrumed upon saiddiaphragm for direct actuation thereby, adjustable means located at oneside of the fulcrum to cushion downward movement of said tilting plate,and a tilting mercury switch mounted on said plate at the opposite sideof said fulcrum for movement with the plate, said mercury switch havingan electrode positioned at a substantial angle to and in the path ofiiow of the mercury and positioned to offer an obstruction to such flowof mercury whereby adherence of the mercury to the electrode will initself cause a delayed action of the switch followed by an actuation ofthe switch with a snap action.

IRVING C. JENNINGS-

